/*
Does ISNULL Do what you think it does?  Do CASE statements have default behavior without an else?
Are data types important?
*/

DECLARE @x CHAR(1) = 't'
SET @x = CASE WHEN @x = 'x' THEN 1 END

--Answer the correct letter for the output
PRINT '@X is now ' + CAST(ISNULL(@x, 'A NULL') AS VARCHAR(50)) + '!'
/*
A) @X is now A NULL!
B) 1  
C) @X is now A!  
D) NULL  
*/

PRINT '@X is now ' + CAST(COALESCE(@x, 'A NULL') AS VARCHAR(50)) + '!'
/*
A) @X is now NULL!  
B) 1  
C) @X is now A!  
D) NULL  
*/

